Wonder Woman is my favourite character (you should all know that), and I like all of her costumes, but I do like some more than others. Here is my list from favourite to least favourite:
Deodato Biker Chick
This sort of goes from one extreme to the other. Although this one might be more functional than the traditional one, it is also a lot more revealing. This one comes from when she lost the right to be Wonder Woman and thus lost her tiara (which I wrote recently in another blog shouldn't have happened). What I like about this one is the colour scheme. Light blue is an underutilized colour in comics and it looks great here. Also tying into the Perez explanation she keeps the battle crest of Wonder Woman because its kind of her birthright.
Newest Version (600 reboot)
I wrote a whole blog on why I like this one. In short its functional and fashionable.
A lot of people on this site think that I don't like the original. That is far from the truth I still really like this costume. A big part of why I like it without thinking it is too revealing was the explanation of its meaning in the Perez arc 'Challenge of the Gods.' (issues 10-13 vol. 2)
This was during a story arc in volume 2 and although it looks all right, is also kind of hokey.